Hi Bryan

On Thu, 05 Jan 2006 21:46:19 -0500, Steve Spence
wrote:


Your math is correct. In NY, with about 3 full sun hours daily max, best
case scenario I'd need a 50 watt panel. 50 watts * 3 hours = 150
watt-hours daily.


Steve and others have pointed out that your basic maths is correct,
but there is a matter of losses to be considered.
One that hasn't been mentioned I think in this thread is that a 60
watt panel does NOT put in 60 watts to your 12v battery unless you use
a clever charge controller like an MPPT (which you wouldn't use for
one panel). This is because panels are not rated at the voltage of the
battery, but at some higher voltage called the maximum power voltage.
One person commented that you should look at the CURRENT provided by
the panel in your situation (rather than the wattage).
A typical figure is for a panel to put about three quarters of its
rated output into the battery (45 watts for a 60 watt panel).
If you need about a 5 amp panel, this will be a panel rated at about
85 watts (= 5 amps X 17 volts).
Personally, I would aim at about a 75 to 80 watt panel for what you
want to do. The difference in price may turn out to be not all that
great anyway as you pay more $ per watt for smaller panels usually.

Eric